1. Field of the Invention
The present invention relates to roof vent dampers, and more particularly pertains to a roof vent damper for automatically closing a roof mounted vent in the event of a fire. Many industrial buildings and houses are equipped with wind driven roof mounted attic ventilators for circulating air through the building attic. While these ventilators are effective during the summer months to reduce air conditioning energy expenditures, these vents create a hazard in the event of fire. In order to overcome this problem, the present invention provides an automatic damper to close the ventilator opening in the event of a fire in order to reduce the supply of oxygen to the fire.
2. Description of the Prior Art
Various types of roof vent dampers are known in the prior art. A typical example of such a roof vent damper is to be found in U.S. Pat. No. 2,183,645, which issued to R. Hansen on Dec. 19, 1939. This patent discloses a roof vent having a pivotal damper plate operable from a remote location through a rope and pulley mechanism. U.S. Pat. No. 2,218,926, which issued to H. Teichmann on Oct. 22, 1940, discloses a damper system for an industrial building roof which utilizes a pair of pivotal opposed dampers. U.S. Pat. No. 2,285,829, which issued to A. Maage Jr. on June 9, 1942, discloses a damper regulator for a rectangular cross section ventilation duct which is formed as a pivotally mounted rectangular plate. The damper includes a regulator for manually adjusting the damper position. U.S. Pat. No. 2,923,225, which issued to C. Massey on Feb. 2, 1960, discloses a roof ventilator having a pivotal damper plate which is biased to an open position by a counter weight and is manually closable by a rope. U.S. Pat. No. 4,759,270, which issued to J. Lindeen on July 26, 1988, discloses a vent cap cover for a recreational vehicle vent including a pivotal damper.
While the above mentioned devices are directed to roof vent dampers, none of these devices disclose a damper which is automatically closed by separation of a fusible link at an elevated temperature to provide a fire safety measure. Additionally, none of the aforementioned devices disclose a method of forming an automatic roof vent damper by providing a dumbbell shaped cut-out in a sheet metal plate and folding the plate along a transverse central fold line to form an interior linear guide track for a damper plate. Inasmuch as the art is relatively crowded with respect to these various types of roof vent dampers, it can be appreciated that there is a continuing need for and interest in improvements to such roof vent dampers, and in this respect, the present invention addresses this need and interest.